EPUB Footnotes Need a Return Route

Treat the note as a short journey

A superscript is not a footnote merely because it looks like one. In a reflowable book, the reader may enlarge type, search, listen, or arrive from a link. The useful unit is therefore a route: reference to note, note back to the same sentence, and language that remains intelligible when the screen has changed. EPUB structural semantics name noterefs and notes, but markup is only the beginning of the editorial question.

Build a three-part record

Give the reference an ID, the note an ID, and the return link a destination that identifies the reference rather than a guessed page. A chapter with two notes should not send both returns to the first note marker. For example, `n12-ref` can link to `n12`, and the note can return to `n12-ref`. Keep the displayed number in the body and the note list synchronized from the same source, not by retyping either one.

Read the difficult cases

Check a note at the end of a sentence, one in a quotation, and two consecutive markers. Then follow a link from the second chapter and use the return control. The worked failure is familiar: note 12 opens correctly, but its return lands at note 11 because copied markup retained an old fragment. A validator may accept that file; only the route exposes the editorial error.

Keep content in the note

A note label should announce enough purpose to orient a reader who reaches it out of sequence. Expand an unexplained abbreviation on first use where the note needs it, and make an empty or duplicate note a production query. If a long note becomes an essay, consider whether it belongs in an endnote section, an appendix, or the main argument. The decision is about reading burden, not a universal length rule.

Leave the check visible

Add a note-route row to the release checklist: reference count, note count, returns sampled, and exceptions. Record the reading system and version only when actually inspected; do not turn a single view into a compatibility claim. When an edition changes, rerun the check after note renumbering and after conversion, since each step can alter fragments. The result is modest but useful: a reader is not stranded in the apparatus.

Also test a reference in linked preliminary matter and a return after a chapter title, because conversion templates sometimes rename or remove IDs outside the main body. A missing return is a release-blocking defect when apparatus is necessary to understand a claim; otherwise record the decision and repair target. The checklist is a record of observed routes, not a promise about features the team did not inspect.